Friday, 27 April 2012

Chatham an urban nuclear waste dump and a lasting legacy of the nuclear submarine programme

Background

Chatham Dockyard played a key part in the United Kingdom’s nuclear propulsion programme. Refitting and refueling of nuclear submarines was carried out at Chatham from 1970 until March 1983. These activities gave rise to radioactive waste which had to be disposed of. Higher activity wastes were disposed of to BNFL Sellafield in Cumbria. However some of the lower activity wastes were disposed of by local burial within the Dockyard site. This was done with the agreement of the Regulator HMIP (reference 1) on the assumption the waste contained short lived Cobalt 60 which would decay away over a period of 20 to 30 years. In interesting note that in an answer to a PQ about radioactive waste arrangements at Chatham, there was no mention of the disposal of radioactive waste by burial at Chatham. Hansard (26 Nov 2002: Column 172W)

Approximately 300 cubic meters of radioactive waste was buried between 1968 and 1986 - reference 2

Risk assessment

Reference 6 to quote the MOD “The risk assessment for the disposal of radioactive waste by burial Chatham - It has not been possible to locate this information, it would have predated the approvals granted by the Department of the Environment in 1980 and has not been located in any of the files recovered”. This is a significant failure in the MOD’s corporate memory.

Cobalt 60 and Carbon 14

Cobalt 60 has a short half live of around 6 years, so that after about 24 years the amount of radioactivity will have fallen by approximately 93%. It was on this basis that it was considered safe to dispose of the waste by local burial.

Reference 7: the attached MOD letter dated 13 October 2008 clearly shows that whilst environmental monitoring for Cobalt 60 was being carried out, it was not for Carbon14. This despite the knowledge dating back to 2001 that Carbon14 may be present.

Burial site

It is notable that the burial site remains MOD property this suggests that the risks from the buried waste are not insignificant. The site is walled off by a 3 metre high wall, whilst the site its self has reverted to scrub and woodland.

Google Earth view showing the dump site at Chatham out-lined in red

As can be seen from the image above the burial site the immediate area is undergoing extensive redevelopment including the water-front, a new marina and housing etc.

View of the dump site from Pier Approach Road the dump is behind the wall and appears to be heavily wooded

Conclusion

The assumption that Cobalt 60 was only significant radionuclide present in the waste buried at Chatham was mostly likely wrong.

The non-availability of a risk assessment or safety case for the burials a Chatham is a serious failing of corporate memory and does little to engender public confidence in the MODs ability to manage the safety of legacy issues over the medium and long term.

In the absence of any available safety case, the MOD in conjunction with the Environment Agency needs to publish a revised safety case for the burial site to take account of the presence of Carbon 14 in the waste. The safety case should also demonstrate that the burial meets current standards and regulatory requirements to ensure both environmental and human safety. If this cannot be done to the satisfaction of stakeholders and the Regulators serious consideration must be given to remediation of the site.

The situation at Chatham does little to improve public confidence in the Governments policy and the NDAs strategy for managing radioactively waste nationally and the MOD in particular. It remains to be seen how the MOD will respond to issues surrounding the waste dump at Chatham, but if Dalgety Bay is an indicator, the signs for speedy action are not good.